Apparatus and process for separating and recovering fine metallic particles from pulp



A. C. THANE.

APPARATUS AND PROCESS FOR SEPAR ATING AND RECOVERING FINE METALLICPARTICLES FROM PU LP.

APPLICATION FILED APR.23 I918- 1 377- 780 Patent d May w, 1921.

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Patented May 1th, 1921..

Application filed April 23, 1918. Serial No. 230,368.

To all whom it may concern.

Be it known that I, ARTHUR C. THANE, a citizen of the United States, anda resident of Chewelah, county of Stevens, and State of Washington, haveinvented a new and useful Apparatus and Process for Separating andRecovering Fine Metallic Particles from Pulp, of which the following isa specification.

My invention relates to an apparatus and process for the recovery ofmetalliferous matter from ores, gravels, sands and the like.

An object of the invention is to provide a process for the recovery ofthe very fine particles of valuable metal from tailings, dredge sands,slimes and pulps.

Another object of the invention is to provide an apparatus with which myprocess may be performed.

The invention possesses many other features of advantage, some of which,with the foregoing, will be set forth in the following description ofthe preferred form of my invention which is illustrated in the drawingsaccompanying and forming part of the specification. It is to beunderstood that I do not limit myself to the showing made by the saiddrawings and description, as I may adopt variations of the preferredform within the scope of my invention as set forth in the claims.

Referring to said drawings:

Figure 1 is a longitudinal vertical sectional view of the apparatus withwhich my process is performed.

Fig. 2 is a plan view of the apparatus.

Fig. 3 is a vertical sectional view on an enlarged scale of a portion ofthe amalgamated plate and the support for the same.

. Broadly stated my process includes the use of an amalgamated plate ofparticular construction above a body of pulp or other liquid in whichfine, free particles of valuable metal are in suspension, and in sotreating the liquid by properly directed currents of fluid, that bubblesof the fluid are formed in the liquid, and which, rising to the surface,carry with them the fine particles of value and deposit the values uponthe plate which is closely spaced to the surface of the pulp. in otherwords the bubbles produced by the air float to the top of the fluidlevel and become attached to the amalgamating device, the surface ofwhich is preferably disposed so as not to be washed or scoured by thepulp passing through the tank.

he process may be used in connection with the recovery of valuableparticles of coarser sizes, but its chief value is believed to he 1n therecovery of the excessively small particles, such as float gold, whichusually escape in the tailings, and in the working of dredger sands,muds and other deposits in which the values are too fine to recover bypreviously existing methods. For conve1iience, i shall use the term,pulp to designate the value bearing material treated by my process, andthis term will be understood to include sands, slimes, gangue, muds orany other mixture of valuable particles, waste matter and liquid.

The apparatus includes a tank 2 for contamlng the pulp to be treated.Preferably the tank is narrower at one end than at the other andnarrower at the bottom than at the top. A diving board or screen 8 isdisposed at the narrow end adjacent the inlet so that the incomingmaterial will not produce obectionable currents in the body of the pulp,

, and a lip 4C is arranged at the opposite end of the tank at such aheight as to maintain the pulp in the tank at substantially a constantlevel. A launder 6 is arranged below the lip 4 to carry 01f thedischarge.

Preferably the bottom 7 of the tank is given a slope toward thedischarge end and a discharge passage 8 normally closed by the valve 9provides means for removing the heavier particles which settle upon thebottom of the tank and are gradually conveyed toward the lower end.

Arranged upon the bottom of the tank are one or more pipes 11 providedwith spaced apertures 12 therein, whereby a fluid such as air or water,but preferably air may be introduced into the pulp for the purpose ofcreating bubbles therein.

Supported at the top of the tank upon suitable cross bars 18, byadjusting screws 14 is a plate 16 which may be of wood or other suitablematerial. Upon the under surface of the plate 16 is a thin plate 17amalgamated on the lower side, and spaced a short distance below theplate 17 is a thin foraminated plate or screen 18 which is amalgamatedupon both sides. The amalgamated plates are detachably secured to thebacking plate 16 by bolts 19 passing through all three plates, a bushing21 being disposed upon the bolts between the amalgamated plates toproperly space them. The adjusting screws 14 are manipulated to levelthe amalgamated plates and position them preferably just above thesurface of the pulp in the tank, and fluid preferably air is introducedinto the pulp through the pipe 11. The air bubbles thus formed passupwardly and break upon the surface, carrying with them the minuteparticles of values held in suspension in, or floating upon the pulp. Itis probable that surface tension in the bubbles within the pulp as wellas the agitation of the pulp by reason of the movement of the bubblestherein, and also the surface tension in the bubbles forming any frothwhich may collect on the surface of the pulp, all contribute a part inthe conveyance of the fine values to the amalgamated plates. Some ofthese particles will be caught upon the lower surface of the foraminatedplate; other particles will be carried through the apertures in theforaminated plate and will be caught by the upper surface thereof or bythe lower surface of theupper plate 17. The pulp fluid carried inbetween the plates will of course drain back into the body of pulpbelow, and the air, having served its function escapes at the edges ofthe plates.

At desired intervals the amalgamated plates are taken from the apparatusand the amalgam removed by the usual means.

I claim:

1. In an apparatus of the character described, a tankadapted to containpulp, an amalgamated plate, means for suspending said plate adjacent tothe surface of the pulp in said tank, and an amalgamated foraminatedplate disposed between and spaced from said first plate and the surfaceof the pulp.

2. In an apparatus of the character described, a tank adapted to containpulp, an amalgamated plate, means for suspending said plate above andclosely adjacent to the surface of the pulp in said tank and means forintroducing jets of fluid into said pulp adjacent the bottom thereof,whereby the fine valuesin the pulp are carried upwardly into contactwith said plate by the bubbles formed in the pulp by said fluid.

3. In an apparatus of the character described, a tank adapted to containpulp, an

amalgamated plate, means for suspending said plate adjacent to thesurface of the pulp in said tank, an amalgamated foraminated platedisposed between and spaced from saidfirst plate and the surface of thepulp, and means for producing bubbles of fluid in said pulp, whereby thefine values in the pulp are entrained in said bubbles and carried intocontact with said plate.

4. The process of recovering metalliferous particles from pulp whichconsists in producing bubbles within the pulp and allowing the bubblesas they emerge from the pulp to contact with an amalgamated plate.

5. The process for recovering metalliferous values from liquid pulp,which consists of flowing the pulp into a tank having a liquid dischargeso disposed to maintain a substantially normal level and depth of liquidin the tank and having an amalgamat' ing surface slightly above thelevel so as not to be scoured by the flowing pulp, and discharging airinto the pulp in such manner as to produce bubbles to catch and conveythe fine metallic particles to the surface of the pulp and intoproximity with the amalgamated surface and so that the bubbles break inclose relation'to the said surface.

6. The process .for the recovery of fine metallic particles in liquidpulp, which consists of flowing the pulp through a tank having anormally constant liquid level; aerating the liquid to form air bubblesto entrain the metallic particles and carry them to the surface of theliquid in the tank, and

catching the bubbles on an amalgamating surface disposed above theliquid so that the surface is not washed by the pulp.

'7. Inan apparatus for the recovery of fine metallic values by theflotation process, a tank through which liquid pulp continually passes,means for introducing a gaseous fluid into the tank to produce bubblesto form vehicles for the fine metallic particles, and an amalgamatingplate disposed slightly above the normal pulp level so as to preventscouring action by the flowing pulp and to be engaged by the ladenbubbles.

8. In an apparatus for the recovery of fine metallic values by theflotation process, a tank through which liquid pulp continually passes,means for introducing a gaseous fluid into the tank to produce bubblesto form vehicles for the fine metallic particles,'and an amalgamatingdevice disposed ust above the normal level of the pulp liquid andcomprising a lower foraminous member and an upper imperforate plateforming therebetween a collecting space for the bubbles.

In testimony whereof, I have hereunto set myhand at San Francisco,California, this 10th day of April, 1918.

In presence of- C. S. EVANS;

